In a large vessel stir the oil, three eggs and yogurt without using a mixer or blender. Dissolve yeast in a little crushed lukewarm water. Was added to the mixture together with the sugar and stirred. Under continuous stirring, add the flour. The dough should be firm, but soft and plastic. The dough is left in a covered container of relatively warm place to rise by one to two hours. For the filling is cut leeks into small pieces and stew in a little oil. Add the minced meat, preferably beef, and stir until turns white. Of hard-boiled eggs cut egg whites into small pieces. Crushed egg yolks and mix with the contents of the pan. The risen dough is rolled and cut into squares (about 10 cm). In the center of each square was placed a spoonful of the filling and the edges are pressed so as to obtain a triangle. So made pirozhki fry in a large amount of well-heated fat. classic Russian dish, which is usually accompanied by tea or broth. With the composition of the filling can improvise Besides the pirozhki are fried and baked in the oven.